Why did the Ottomans become the sick man of Europe?

One thing I have found confusing about the Ottomans is how they went from the conquest of Constantinople in 1453 and the reign of Suleiman the Magnificent in the 1500s to then begin a slow decline by the 1600s according to overviews I’ve seen.

Why when Britain, France and Russia were able to stay major world powers well into the 19th and early 20th century did the Ottomans fall
so far behind?